The present invention relates to a manufacturing apparatus and method for a semiconductor device, for example, used for forming a film by supplying a reaction gas to the surface of a semiconductor wafer while heating the rear surface of the semiconductor wafer.
In recent years, as a semiconductor device is requested to realize lower price and higher performance, higher productivity in film forming process of a wafer and higher quality such as improvement in uniformity in film thickness is also required.
To satisfy such requirements, a back heating method is employed, which uses a single-wafer-processing epitaxial growth apparatus, supplies process gas while rotating a wafer at high speed of 900 rpm or higher in a chamber, and heats the wafer from the rear surface by using a heater.
Ordinarily, a heater element that constitutes the heater is fixed and connected to an electrode part as a support member in a plane of the heater element using a bolt and the like. However, since a connecting portion is deformed by heat and a resistance value is increased by the deformation, Japan Patent Application Laid-Open No. 2007-288163 (FIGS. 1, 2, and the like) discloses to provide a heater electrode portion integrated with a heater element and to connect the heater electrode portion to an electrode part apart from the heater element.
Sintered SiC is used to the heater composed of the heater element and the heater electrode portion due to its processing performance. Then, impurities are added to the heater electrode part to provide a conductive property as well as SiC coating is applied to prevent diffusion of the impurities.
When epitaxial film formation is performed using the heater, a problem arises in that the heater is deteriorated by sublimation of SiC. Then, a resistance value is increased, strength is lowered, a film forming temperature is varied, and the heater is broken by the deterioration of the heater. In contrast, with a recent requirement for improvement of productivity and a film quality in the epitaxial film formation, since it is further required to perform a process at a high temperature, there is tendency that a larger load is applied to the heater.
To cope with the problem, Japan Patent Application Laid-Open No. 2008-4767 (claim 1 and the like) discloses a method of supplying an SiC source gas into a chamber from thereabove and forming an SiC film in a sublimated portion of a heater, thereby increasing a life of the heater.
However, the method has a problem in that since a gas to be supplied must be replaced by stopping an apparatus once, a throughput is inevitably lowered.
Further, since sublimation more proceeds particularly in a connecting portion where a heater element is connected to a heater electrode portion because an electric field is concentrated to the connecting portion, the connecting portion is more deteriorated. However, when an SiC source gas is supplied from above the heater element, since the connecting portion is shaded by the heater element, it is difficult to selectively form a film to the connecting portion.